Many consistency or viscosity measuring devices submerge blade transducers, coupled to a shaft-like probe member, into a medium flowing in a pipeline, such as described in U.S. Pat. No. 3,796,088, by Gustafsson et al.; U.S. Pat. No. 4,062,226, by Hietala; U.S. Pat. No. 4,148,215, by Hofstetter, Jr.; U.S. Pat. No. 4,365,519, by Hietaranta; U.S. Pat. No. 4,677,846, by Lundberg; U.S. Pat. No. 4,757,708, by Hietaranta; and U.S. Pat. No. 5,369,987, by Nettamo et al. Such devices measure various parameters of a medium flowing in a pipeline, such as the viscosity of a liquid, the concentration of solid matter in a liquid, consistency of flowing pulp stock or paper stock fibre, etc.
As can be readily viewed from the above identified patents, the length of the blade transducers extend in the direction of the flow of the medium under test wherein the forces of the medium that are acting upon the blade transducers and probe members are measured to determine the desired parameter of the medium. In order to achieve accurate measurements, the total surface area of the blade transducers should be maximized wherein the height and length which are parallel to the flow of the medium are maximized and the width (the cross-section presented or opposing the flow of the medium) is minimized. As can be observed, such length is significantly greater than the inside diameter of the transducer port into the pipeline. Therefore, to install such consistency measuring devices, the blade transducers thereof must be carefully maneuvered in order to be submerged in the pipeline, when such pipeline is out-of-service. Since the known measuring devices are costly to remove in the event of a malfunctioning component, pipeline servicing, erosion of a component or cleaning of components, the known measuring devices do not provide for maintenance and repair of the measuring devices while the pipeline is in service.
Removal of the blade transducer and probe member of the known measuring devices requires the pipeline to be placed out-of-service. Moreover, the known measuring devices are not capable of removing or inserting the blade transducers from the medium without shutting down the pipeline and related processes, without compromising the integrity of or disturbing the connection (sealed, flanged, welded or otherwise) between the measuring device and the transducer port in such pipeline and significantly minimizing the environmental exposure of the medium.
Other patents present in the art are U.S. Pat. No. 3,734,119, by Nudds; U.S. Pat. No. 4,875,362, by Skallen; U.S. Pat. No. 5,157,962 by Fitzgerald et al.; and, U.S. Pat. No. 5,349,848, by Driver all of which are directed to measuring devices having blade-like transducers submerged in a medium, but do not meet the needs of the measuring device of the present invention.
Depending on the industrial applicability, it is highly desirable to remove from time-to-time the submerged blade transducers from the pipeline, while such pipeline is in service. In the food industry, such as, without limitation, plants which produce tomato juice, orange juice and ketchup, the pipeline and associated equipment need to be sanitized. In order to remove such blade transducers of known measuring devices from the pipeline, the pipeline must be placed out-of-service and the measuring device, as a whole, must be disassembled in order to retract (i.e., remove) the blade transducer. As is evident, this process is time consuming and costly.
In the paper industry, some of the chemicals used in the process of making paper can corrode the sensing means of the probe members and erode the surfaces of such blade transducers and probe members. Therefore, the blade transducers and sensing means must be repeatedly monitored and replaced. Again, in order to retract the blade transducers of known measuring devices, the pipeline must be placed out-of-service and the measuring devices, as a whole, must be disassembled in order to retract (i.e., remove) the blade transducers of known measuring devices. In the event, a log (dried out paper pulp) passes through the pipeline, all the blade transducers in the pipeline will be damaged and/or dislodged, since such blade transducers cannot be easily and quickly retracted (i.e., removed) from the pipeline. The dislodged blade transducers flow down the pipeline and into the processing equipment which can cause damage to such equipment.
In other materials application, as well as the above mentioned applications, build-up of material on the blade transducer and sensing means are common and such build-up can render the measurements less effective. Therefore, it is highly desirable to retract the blade transducers from the pipeline for cleaning.
It can be readily seen that there exists the continuing need for a measuring device which maximizes the surface area of a blade transducer, which is swingably coupled to a probe member, and utilizes the force of the medium, such as a slurry, flowing in an in-service pipeline to swingably align the blade transducer in a desired measuring position and wherein the swingable coupling of the blade transducer to the probe member provides for the retraction from and insertion into the medium flowing in the in-service pipeline for repairs, replacement, or sanitization or other maintenance or servicing of such blade transducer, without shutting down the pipeline and related processes, without compromising the integrity of or disturbing the connection (sealed, flanged, welded or otherwise) between the measuring device and the transducer port in such pipeline and significantly minimizing the environmental exposure of the medium. Moreover, the retractability feature of the swingable blade transducer enables other components of the measuring device to be replaced, repaired and sanitized or otherwise maintained or serviced, as desired